This invention relates to the field of projection systems, and more particularly to the field of projection systems for vehicle simulators.
Simulation systems are often used to simulate systems and vehicles, especially aircraft, for training users or pilots. In these simulation systems, an out-the-window scene is generated and displayed to the user. The image is generated as pixels and projected on one or more projection screens to constitute a field of view covering a substantial area. The projected out-the-window (OTW) image is consequently so much enlarged that it has a rather coarse, low resolution.
It is desirable to display at least certain objects, such as other aircraft, in small enough resolution to train a user to see and recognize targets at great distances such as those in the real world, i.e., at or near eye-limiting resolution. As an example of the target resolution now desired, it has been expressed that a desirable standard would be that a trainee in an aircraft simulator would be able to discern the attitude of a target aircraft at a simulated distance of two to three miles.
This level of resolution cannot be achieved with the coarse projected pixels of the larger OTW imagery. To try to improve target resolution, projector systems have been developed that include a separate higher-resolution target projector that projects a single higher-resolution target image on the screen superimposed with a lower resolution background image.
The prior art projectors, however, have the very substantial drawback that they can project only one target on the screen at a time. If a simulation is desired in which multiple targets are present on the screen, a second projector must be provided at substantial additional cost, especially where the simulator has a large number of screens are used. For example, in a Raytheon SimuSphere simulator system, there are nine faceted screens. To provide enough single-target projectors to afford four active targets in the overall field of view would require four single-target projectors for each screen, totaling 36 target projectors needed. With the cost of each current-technology target projector at about 100,000 U.S. year 2000 dollars, such a system would be too expensive to be practical.
In addition to being very expensive and having only single target functionality, prior art target projectors are generally too large, making them difficult to package, and also difficult to place in a structural environment inside or around the simulator that is already crowded with other projectors and support equipment. Furthermore, the prior art projectors often are monochrome, reducing the realism of the projected display.
Accordingly it is an object of the invention to provide a projection system that allows for the projection of multiple high-resolution images with a single projector.
This object is achieved by providing a projector system having an image display with at least two image display portions each displaying a respective image. At least two projection assemblies are provided, each associated with a respective image display portion. These projection assemblies each receive a respective image from the associated image display portion and project this image onto the projection screen. The projection assemblies each include a system for independently and selectively locating the projected image on the screen.
In a preferred embodiment, the projection assembly includes a stationary mirror supported adjacent the image display portion receiving the image therefrom and reflecting said image outwardly from the image display to the movable mirror.
Preferably, the stationary mirror has an upper end portion and a lower edge portion. The lower edge portion is adjacent the image display portion and the mirror extends obliquely upwardly therefrom. Most preferably, the stationary mirror flares outwardly from the lower edge portion, and the stationary mirrors are grouped together over the image display, with the lower edge portions of adjacent stationary mirrors being supported generally perpendicular to each other.
In another aspect of the invention, the system for locating the projected image includes a movable mirror supported on a controlled support system selectively positioning the movable mirror in varying angular positions.
It is further an object of the invention to provide a method of projection that overcomes the disadvantages of the prior art. According to the inventive method, a background projector and a target projector are provided, both positioned so as to project images on a screen. The target projector includes a target image display having at least two image display portions each configured to display a respective image. Each image display portion has associated therewith a respective target projection assembly for receiving and projecting the image on the projection screen. Each projection assembly includes a system for independently and selectively locating the projected target image on the screen. The method further includes causing the background projector to project a background image on the screen, forming target images on said display portions of the target projector, and causing the target projector to locate said target images on said projector screen. The target images are at a higher resolution than the background image.
According to a preferred embodiment, the target images are formed with a distortion to compensate for any angular alignment of the screen with the target projector.
Other objects and advantages of the invention will become apparent from the specification herein.